In general, a driver seat, an occupant seat, and seats as other occupant seats, which are installed in front of and behind the interior of a vehicle, have various comfort devices for convenience of occupants.
The comfort devices have a sliding function of adjusting forward and rearward pushing/pulling of the seat, a reclining function of adjusting an inclination of a backrest, etc., according to body types of the occupants.
In addition, a vehicle, which is recently developed or has a predetermined reference or more, also includes a pumping device having a seat lifting function of adjusting a height of a seat by receiving input from a handle 100 so as to be suitable for occupants, as shown in FIG. 1.
The pumping device is largely configured of a lever unit, a clutch unit, and a brake unit. The lever unit receives operating force of a user and transfers the operating force to the clutch unit. The clutch unit serves to transfer the input operating force of the user to a link means of the seat. The brake unit serves to cut off power input in reverse so as to fix the link means an operation of which is completed.
The lever unit includes a lever bracket which converts vertical operating force of a handle lever installed at one side of the seat into rotational force and transfers the rotational force to the clutch unit. Meanwhile, the pumping device may further include a return portion which returns the handle lever and the lever bracket to initial positions.
The return portion generally includes a return spring. The handle lever and the lever bracket are configured so as to be returned to the initial positions after the operating force of the user is released by action of the return spring.
In this context, Japanese Patent No. 4515146 B2 discloses a return spring having two pole portions formed at one side thereof. In the return spring, the two pole portions are configured of a first pole portion which engages with an input side member and a second pole portion which prevents separation of the spring through increase of a center diameter thereof when a lever is operated. However, the return spring has complicated manufacturing processes and many management dimensions since the two pole portions are formed at one side of the return spring, and thus a clearance of the lever may occur. In addition, noise may occur due to collision between the return spring and other components while the center diameter of the return spring increases when the lever is operated and the center diameter decreases when the lever is returned to an initial position.
Meanwhile, Korean Patent No. 10-0921849 discloses a structure in which a first elastic member for returning a lever is integrated with a second elastic member for returning a clutch unit. However, the structure has a problem in that the second elastic member instantaneously has decreased elastic force while the first elastic member is separated by external force when the lever is operated, resulting in generation of slip since torque is not transferred from an input side member to a control member.